As usual, there should be a bit of flexibility in there. I am not saying “oh, it’s 0C, therefore ALL water in all town is frozen , lets wait until it gets to 1C so all water melt”. But more on the line “oh, its around 0C (+ or - 5C), lets be careful while driving because some of the streets might have ice”. Farenheit freezing temp is 32 I think? Thats VERY arbitrary. A lot more than C.